Direct empirical relationships between stocking density and fish yield have been documented for many sets of ponds, reservoirs, and lakes located worldwide. Exceptions, however, have often been observed. This study explores the empirical relation between stocking rate and yield in waterbodies ranging from ponds to lakes in both temperate and tropical regions. A variety of published data was used comprising measurements of yield, stocking density, mean size at stocking, presence of self-sustained fish populations, lake area, and latitude for more than 700 waterbodies.

Fish yield was strongly related to fish stocking density for both the combined data, and for temperate and tropical subsets. Regressions differed significantly between temperate and tropical waterbodies. Furthermore, large waterbodies with self-sustained fish populations and small systems under intensive aquaculture deviate positively from overall regression lines, in both data subsets. As expected, at low stocking densities yields are higher in tropical systems than in temperate ones. However, there were no significant differences in maximum yield between regions.

Fish yield varies nonlinearly with stocking density for both temperate and tropical systems. At very low stocking rates, increases in stocking correspond to little change in yield. At intermediate stockings, the rate of increase of yield accelerates with increasing stocking density; a concurrent increase in external energy inputs may be hypothesized.